Fig. 5: PD-L1 identified as a downstream effector of ICAM1-Wnt/β-catenin signaling, promoting immune evasion.

a RT-qPCR analysis of Icam1 expression in GL261 cells infected with Icam1 or vector control lentivirus. b Cell proliferation assays using GL261-Icam1 or GL261-vector cells. c Luminescence images of mice bearing orthotopic xenografts of GL261-luc cells infected with Icam1 or vector control lentivirus. d Kaplan-Meier survival curves of mice as in (c) (n = 6, 5 × 10⁴ cells/mouse). e IB analysis of ICAM1, β-catenin, cyclin D1, PD-L1, CD47, CD24, and B2M expression in GSC209, 83, and 528 GSCs infected with shICAM1-1/−2 or shCtrl lentivirus. f IB analysis of ICAM1, β-catenin, cyclin D1, PD-L1, CD47, CD24, and B2M expression in X01 GSC, 131 GSC, and GL261 cells infected with ICAM1 or vector control lentivirus. Correlation analysis of ICAM1 and CD47 or PD-L1 in all glioma (g) and GBM patient samples (h). Data were collected from the CGGA portal. IB (i) and cell proliferation (j) analysis in 528 GSC treated with anti-ICAM1 antibody (1, 2, 4 µg/mL) or isotype antibody. β-catenin, cyclin D1, PD-L1, CD47, CD24, and B2M expression were analyzed in (i). IB (k) and cell proliferation (l) analysis in 83 GSC treated with anti-ICAM1 antibody (4 µg/mL) or isotype antibody. β-catenin, cyclin D1, PD-L1, CD47, CD24, and B2M expression were analyzed in (k). IB analysis of ICAM1, β-catenin, cyclin D1, PD-L1, CD47, CD24, and B2M expression in X01 (m) and 131 GSCs (n) infected with ICAM1 or vector control lentivirus, and treated with ICG001 (10 µM) or vehicle. o Schematic illustration of the proximal region of human pGL3-CD274 promoter (upper). Luciferase reporter assays of TCF/LEF activity in 293 T cells transfected with luciferase reporter vectors containing TCF/LEF sequences of CD274 promoter (lower). p Killing efficiency of anti-ICAM1 (4 µg/mL), ICG001 (10 µM), and anti-PD-L1 (10 µg/mL) in 83-luc GSC infected with CD19 lentivirus and co-cultured with CD19-CAR T cells. q Schematic illustrating the role of ICAM1 in regulating the Wnt/β-catenin/PD-L1 signaling pathway. Created in BioRender. Yin, J. (2025) BioRender.com/vhr5dod. Statistics: a, b, j, l Data are presented as mean ± SD (n = 3, biological replicates), two-tailed Student’s t-test. d Log-rank test (n  =  6 mice/group). g, h Two-sided Pearson correlation test. o Data are presented as mean ± SD (n = 3, biological replicates), one-way ANOVA with Tukey’s multiple comparisons test. p Data are presented as mean ± SD (n = 2, biological replicates), two-tailed Student’s t-test. Image: e, f, i, k, m, n Representative blots (n = 3, biological replicates). The samples derive from the same experiment but different gels for β-catenin with cyclin D1, another for PD-L1 with CD24, another for CD47 with B2M, and another for ICAM1 with GAPDH (e, f, m, n) were processed in parallel. The samples derive from the same experiment but different gels for β-catenin with cyclin D1, another for PD-L1 with CD24, another for CD47 with B2M, and another for GAPDH (i, k) were processed in parallel. GAPDH was used as a loading control. Source data are provided as a Source Data file.